Recently a friend and I decided to change our summoner names for fun. We are on each others friend's lists and understandably it does take time for the name change to take effect in some cases, however, we changed our names about three weeks ago. So to the point of the glitch: we played a ranked match, he left the stats page after the match ended, I hit play again which invited him, but the invite was sent to his original summoner name and not his new one, therefore he did not receive the invite.
Steps to replicate:
1. Create two accounts
2. Change summoner names
3. Play duo queue match (WIN IT! ;D)
4. At stats page, have person who did not start duo queue leave
5. Have person who invited press play again
6. Observe invite sent to old summoner name